If the boys have a painful kneecap, the causes include chondromalacia patella, kneecap injury, knee meniscus injury, degenerative diseases, rheumatoid immune diseases, etc., as follows: 1, chondromalacia patella: this condition is likely to lead to kneecap pain in boys, especially after running and jumping activities, the pain is particularly pronounced. 2, kneecap injury: this condition can also cause The kneecap area has swelling, pain, activity limitation. 3, knee sports injury: is a common cause of knee pain in young and middle-aged people, including knee meniscus injury, anterior and posterior cruciate ligament injury, lateral collateral ligament injury will lead to knee joint pain symptoms. 4, degenerative diseases: boys have the kneecap area degeneration, osteophytes, is also prone to cause kneecap pain. 5, rheumatoid immune diseases: For example, rheumatoid arthritis, rheumatoid arthritis after erosion of the knee, also easy to cause kneecap pain. So in the case of boys with knee pain, we must identify the cause of the cause of treatment to alleviate the pain symptoms, the pain is obvious when you can through the hot compresses, acupuncture, moxibustion and other therapies to alleviate the pain symptoms.